Font Weight Number-Name Mapping
Conventional named 100..900 CSS weight mapping, not available font face/variable in stance or perceived stroke weight; other CSS numeric weights are not invalid CSS but outside this lookup. Explicit caller font/layout/reference context; not a shaping engine, actual page layout or accessibility certification.
Description
CSS weight names conventionally correspond to the hundred-step values from 100 through 900.
When to use Font Weight Number-Name Mapping
Use this tool when you need to reproduce the stated calculation from measured records or independently selected model inputs. Establish the font version, feature, layout, physical or CSS units, and matched reference basis needed for this calculation.
How to use Font Weight Number-Name Mapping and understand its results
- Establish the font version, feature, layout, physical or CSS units, and matched reference basis needed for this calculation.
- Enter cssNominalWeight, following the field table and rules below, then run the tool.
- Read conventionalWeightName. Use the output meanings below to interpret units, signs, flags, and any nested result fields.
- Correct reported input issues and run again. For a successful result, check the stated evidence coverage and assumptions before using it in your review.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| cssNominalWeight | CSS nominal weight | number | Required |
Enter one supported numeric value: 100 thin, 200 extra-light, 300 light, 400 normal, 500 medium, 600 semi-bold, 700 bold, 800 extra-bold, or 900 black. Other numeric values are outside this lookup even where CSS permits them.
name=conventionalWeightTable[String(weight)] Symbols follow the input and output meanings and the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| conventionalWeightName | Conventional weight name | string |
{
"input": {
"cssNominalWeight": 600
},
"output": {
"conventionalWeightName": "semi-bold"
}
}Limitations and assumptions
The calculation uses declared units and font or layout assumptions. It does not shape glyphs, lay out actual pages, or certify accessibility or print quality.
Missing required fields, unknown fields, wrong types, and violated calculation rules are input issues. Numeric values must be finite; nonfinite results are rejected.
Alternative or Complementary methods
For a related review, use Large Text 18pt/24px Threshold Classifier: WCAG large-text size categories use CSS-equivalent point thresholds and distinguish bold from regular text. This screen evaluates only that size category, which is one input to a contrast review. For a complementary step, use Average Kerning Pairs Per Font Lookup: Kerning inventory counts depend on font version and table representation. A keyed reference comparison can audit the declared count without treating class-based GPOS kerning as a simple universal pair list.
References
-
Font Weight Number-Name Mapping — tool.io
Similar or alternative tools
- Large Text 18pt/24px Threshold Classifier
WCAG large-text size categories use CSS-equivalent point thresholds and distinguish bold from regular text. This screen evaluates only that size category, which is one input to a contrast review.
- Average Kerning Pairs Per Font Lookup
Kerning inventory counts depend on font version and table representation. A keyed reference comparison can audit the declared count without treating class-based GPOS kerning as a simple universal pair list.